Angular rate sensors such as gyroscopes serve as one of the major sensors in inertial navigation and guidance systems. Traditionally, gyroscopes have been implemented as large mechanical devices such as rotating wheel gyroscopes or other large metallic devices with dimensions of inches. These types of devices have several drawbacks including size restriction, reliability concerns due to the large number of mechanical parts, and high costs associated with precise machine tolerances and tuning.
The use of tuning forks for gyroscopes has been attempted but has been met with limited success. These devices are costly due in part to the effort required to tune the motor resonant frequency to the output resonant frequency and also in part due to the large size of such devices. Thus, large scale production of these types of devices have not proven commercially viable.
In addition, prior art tuning fork gyroscopes have not been able to separate or isolate the drive axis from the sense axis, leading to causing more difficult and complicated manufacturing techniques.
Although a number of attempts have been made to produce solid state, micromachined tuning fork gyroscopes, the prior art devices are made of quartz and still generally of intermediate size. In addition, precision fabrication and assembly techniques as well as assembly costs have limited the success of such devices.